The invention relates to a valve body used for a backflow prevention valve. The backflow prevention valve is provided at a terminal end part of a fuel supply path for delivering fuel into a fuel tank, and functions so that during delivery of fuel from the fuel supply path, a valve is opened by a flow pressure of the delivered fuel to allow the fuel to flow into the fuel tank, and during non-delivery of fuel, the valve is closed to block the fuel inside the fuel tank from flowing back into the fuel supply path.
As a backflow prevention valve for a filler pipe of a fuel tank, there is one disclosed in Patent Document 1. The prevention valve has a structure in which a seal member having a lip part seated in a valve seat part of a valve body is held between a main body member and a spring bearing member. There are several drawbacks in the prevention valve. First, the number of constituent parts is large and the assembly work takes time correspondingly. Second, depending on dimensional accuracy of the main body member and the spring bearing member, the seal member may deform in a wave shape, thereby making it difficult to properly position the lip part in the valve seat part. Third, it is necessary to pay attention to the seal quality between the seal member and the spring bearing member, in addition to the seal quality between the main body member and the seal member.
Patent Document 1: Japanese Patent Publication (Kokai) No. 2000-16099
In view of the problems described above, an object of the present invention is to provide a valve body for a backflow prevention valve that can be constructed suitably with the minimum number of parts.
Further objects and advantages of the invention will be apparent from the flowing description of the invention.